Rotary lawn mowers are widely used by both homeowners and lawn service providers for cutting grass to maintain the tidy appearance of lawns located about residences and buildings. Such lawn mowers typically include an internal combustion engine or electric motor to rotate a driveshaft, and a cutting blade coupled to the driveshaft by a fastener. The cutting blade is therefore rotated, severing individual blades of grass it passes through the grass. The rotating cutting blade generates currents of air that may cause the blades of grass to be lifted upright as the lawn mower advances over the ground, helping to cut the blades of grass to an even length.
The cutting blade is subjected to potentially damaging operating conditions, often contacting sticks, rocks, tree roots, and other debris. Cutting blades wear and become dull over time, losing their ability to effectively cut grass. To replace a conventional cutting blade, an individual typically removes the fastener coupling the lawn mower blade to the rotatable driveshaft, which may be time consuming and difficult to accomplish. The removal and sharpening, or complete replacement of such cutting blades is particularly burdensome for lawn service providers who use fleets of such lawn mowers and cut large amounts of grass on a daily basis.
Some prior attempts at providing a lawn mower cutting blade that may be quickly sharpened or replaced focused on cutting blades having removable and replaceable cutting edges. For example, U.S. Pat. No. 3,563,015 to Renfroe discloses a cutting blade for a rotary lawn mower having detachable cutting edges that are slidably mounted in spaced apart channels on ends of the cutting blade. The cutting blade includes stops extending laterally of the cutting edges to prevent the longitudinal movement of the cutting edges outwardly of the cutting blade.
U.S. Pat. No. 5,018,347 to Feilen discloses an elongate lawn mower cutting blade including a forwardly extending flange and a rearwardly extending flange. Each flange includes a slot extending along the flange spaced apart from an edge end surface of the cutting blade. A replaceable cutting edge having a T-shaped projection extending rearwardly is receivable within the slot.
Other approaches to providing lawn mower cutting blades that may be quickly replaced focused on a blade mount for releasably securing a cutting blade to a lawn mower's rotatable driveshaft. U.S. Pat. No. 4,586,257 to Rittenhouse, for example, discloses such a blade mount for releasably securing a cutting blade to the rotatable drive shaft. The blade mount includes an engaging pin biased with a compression spring extending outwardly from the blade mount face against which the cutting blade rests. The engaging pin projects through a hole in the cutting blade and can be pushed in to release the cutting blade. The cutting blade and blade mount have respective notches and tabs that can be aligned to assist the securing of the cutting blade in the blade mount during use.
These prior approaches, however, may not facilitate cutting blade removal and sharpening, or replacement as easily and quickly as some users may desire. Accordingly, other types of lawn mower blade assemblies that enable quick cutting blade removal and sharpening, or replacement may be desired.